The existing liquid crystal display device includes such structural members as a front frame, a liquid crystal display panel, a rubber frame, an optical diaphragm, a light guide plate, a light source and a backplate. Wherein the backplate is of a hollow structure design (FIG. 1), which is conducive to reduce the weight of the entire module and to save the cost. Meanwhile, this backplate with the hollow design can immediately dissipate the heat generated by the light source during light emitting as well. However, although the hollow design can improve the heat dissipation effect, the light source has an uneven temperature distribution on the hollow backplate. Specifically, the temperature of the light source in the center is higher than that at both ends, which causes the liquid crystal panel to have too concentrated stress at the corner and is thus disadvantageous to the long-term use of the liquid crystal panel.